How Good Is Your Basic Iron Metallurgy?
By
Roy Lobenhofer
As an old man is want to do, I was going through some old files to get rid of some of the clutter. (Of course, it was to make room for other clutter.) In doing that I ran across the material I used to teach a basic iron metallurgy course for non-metallurgist foundry people and it got me to thinking.
Iron metallurgy is rarely taught in school even for metallurgical engineering students (if there are such things anymore). I used to joke that at Illinois Institute of Technology where I went to school they started out this way: “There are two types of metallurgy – ferrous and nonferrous. We will talk about nonferrous later. In ferrous metallurgy, there are two basic types – steel and iron. Now that we have talked about iron, we will direct our attention to steel.”
From what I learned by talking to other metallurgists in the iron foundries, things may have been better in other schools, but not by much. I know when I first started in iron foundries, right out of school, I had a heckuva time. I had been taught that high carbon increases strength and hardness – which it does in steel. I had to retrain myself to remember high carbon in iron decreases strength and hardness.
AFS has some wonderful courses to teach the “metallurgical type” what they need to know, but I have always felt it a tremendous asset if the operating personnel in an iron foundry also has a working knowledge of iron metallurgy. I was fortunate enough to have some clients that felt the same way and I put on some classes for them to try and achieve that.
Of course, it’s one thing to teach a class and it’s another to get across what you’re trying to teach. The only way I knew how to measure whether I was being effective or not was to do some testing afterwards. Following is the test that I gave my students upon the conclusion of the course. I think it is a measure of how well the participants understood what I was talking about and being true false didn’t really intimidate them. Remember, these were not the laboratory people. These were the iron pourers, furnace operators, and molders.
1. If you had a grade 65-45-12 ductile iron casting that was too hard, you should give it a normalizing heat treatment.
True________ or False_________
2. If iron has more carbon than normal and other elements are normal, you should expect the castings to be softer than normal.
True________ or False_________
3. Pearlite is weaker than ferrite.
True________ or False_________
4. Carbide is harder than ferrite.
True________ or False_________
5. If a ductile iron test bar is harder than normal, you should expect the elongation to be greater than normal.
True________ or False_________
6. The primary element the changes graphite from flakes to spheres is molybdenum.
True________ or False_________
7. If a gray iron casting has more chrome than normal, you should expect the castings to be harder than normal.
True________ or False_________
8. If a gray iron test bar is harder than normal, you should expect the strength to be higher than normal.
True________ or False_________
9. Under normal conditions, the thickest section of the casting will be the hardest.
True________ or False_________
10. Under normal conditions the harder/stronger the iron is the less likely you are to experience shrink.
True________ or False_________
It might be interesting for you to see if your employees can answer these questions. If they can, I’ll bet you have a very good operation. If they can’t, you might want to consider some training. However, if you and/or your technical people can’t answer these questions, you most likely have a problem!
By the way, you’ll notice the heavy use of the word “normal” in the test. Technical types can come up with exceptions to almost everything, but I wasn’t trying to teach the exceptions. I was trying to get across what was going on in the everyday operation.
Oh, you’re wondering about the answers (obviously, just to see if I know enough to be writing something like this).
1. False
2. True
3. False
4. True
5. False
6. False
7. True
8. True
9. False
10. False
Did I pass? If you have questions or want my logic for an answer shoot me an email. rwl@lobenhofer.com